In the late 1970's D. P. Attenburrow et al. developed a device for recording sound over the trachea which included a radiostethoscope and a spectrogram analysis of inspiratory and expiratory sounds of horses at rest and during exercise (See, e.g., Attenburrow, D. P., “The Development of a Radio-Stethoscope for use in the Horse at Rest and During Exercise”, Equine Vet J. (1978), 10, (1), 14-17; Attenburrow, D. P., “Respiratory Sounds Recorded From Normal Horses at Exercise” Equine Vet J. (1978), 10, (3), 176-179; and U.S. Pat. No. 4,218,584 to Attenburrow). Later, however, it was found that sounds recorded over the trachea do not necessarily directly relate to the functionally significant respiratory sounds of the exercising horse, see, e.g., Derksen et al. “Spectrogram Analysis of Respiratory Sounds in Exercising Horses”, AAEP Proceedings, Vol. 45, pp.314-15 (1999) (See also, U.S. Pat. No. 6,228,037 to Derksen.) and the U.S. Patent Publication No.: 2002/0156391 A1 to Derksen et al.
In the '037 patent, Derksen et al. advocate the use of a large and cumbersome microphone positioned in front of the horses nostrils and a recording device which can be placed alongside a horse exercising on a treadmill to pick up normal as well as abnormal respiratory sounds and assess pathology of the upper airway based upon the sound patterns produced during exercise, e.g., for detection of laryngeal hemiplegia and dorsal displacement of the soft palate. Derksen's analytical systems, however, are limited in that they are difficult to use on a galloping horse under field conditions, e.g., on a horse with a rider (e.g., breezing or working) on a training track and cannot be used during an actual race or competition event. In addition, the Derksen device, by design, picks up respiratory sounds at close proximity to the nostrils of the horse which, in the galloping horse, can also include extraneous and unwanted sounds, e.g., percussion noise of the hoofs contacting the training surface and wind noise.
As with the Derksen device, the Attenburrow et al. radiostethoscope may be limited in that it cannot conveniently be used under field or actual racing conditions and, moreover, may not be capable of detection of subtle changes in upper airway respiratory sound induced by subclinical pathological change. Thus, there still exists a need in the art for a device and method which enables analysis of such parameters in the equine athlete under field and/or racing conditions.
Once an individual race horse prospect has been selected by its owner and the training and racing process begins, some individual horses will not perform up to their “estimated” or “anticipated” potential. Oftentimes, subtle pathological changes or even slight developmental abnormalities (which may be subclinical or non-apparent to the naked eye) are present in the subject horse's upper airway and can be responsible, at least in part, for the animal's sub-par performance at a particular racing level. Thus, there exists a need in the art for a device suitable for detection of these subtle pathological changes in the upper airway which can be attached directly to the horse and thereby enable recording and analysis of respiratory sounds generated at racing speeds, e.g., during an actual race.
U.S. Pat. No.: 5,853,005 to Scanlon discloses a sound and movement monitor comprised of a transducer with a fluid filled pad held in close contact against a sound or movement source for monitoring acoustic signals transferred into the fluid. The use of a fluid filled medium and transducer, however, presents problems with vibrational movement, e.g., hoof beat percussion from the intensely exercising animal. Thus, there still exists a need in the art for a device which can be attached directly to the horse which enables accurate detection of and analysis of respiratory sounds in the equine athlete exercising under field conditions that does not suffer from these shortcomings.